U.S. patent number 6,039,580 [Application Number 09/116,839] was granted by the patent office on 2000-03-21 for rf connector having a compliant contact.
This patent grant is currently assigned to Raytheon Company. Invention is credited to James D. Arangio, William A. Sciarretta, Paul Setzco.
United States Patent |
6,039,580 |
Sciarretta , et al. |
March 21, 2000 |
RF connector having a compliant contact
Abstract
An RF connector includes an electrical insulator having an
aperture and a conductive contact disposed within the aperture and
having at least one compliant, compressible end. The insulator is
disposed in an aperture of a conductive support plate. When an RF
element is secured to the support plate in use, the compliant end
of the conductive contact is compressed against a conductive pad of
the RF element. In one embodiment, the RF connector includes a
compressible, conductive annular ring disposed concentrically
around the compliant end of the conductive contact and adapted for
being compressed against a ground pad of the RF element in use in
order to effect a coaxial RF interconnection. The conductive
contact may take various forms, such as a watch band pin, a Fuzz
Button.RTM. or a bellows arrangement. The RF connector may include
RF circuitry for interconnection to the RF element and/or may
interconnect the RF element to a second RF element.
Inventors: |
Sciarretta; William A.
(Lexington, MA), Setzco; Paul (Wellesley, MA), Arangio;
James D. (Saugus, MA) |
Assignee: |
Raytheon Company (Lexington,
MA)
|
Family
ID: |
22369551 |
Appl.
No.: |
09/116,839 |
Filed: |
July 16, 1998 |
Current U.S.
Class: |
439/63;
333/243 |
Current CPC
Class: |
H01P
5/085 (20130101) |
Current International
Class: |
H01P
5/08 (20060101); H01R 009/09 () |
Field of
Search: |
;333/33,243
;439/63,66,289,333,581,700 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
D Strack, et al., "Solder Free Interconnects for Mixed Signal (DC/
Microwave) Systems" 1996, EEE MTT-S Digest, pp. 231-234. (no
month). .
"High Performance Test Socket", Tecknit Interconnection Products,
129 Dermody Street, Cranford, NJ 07016, 9 pages of product
information, undated. .
"IDI Battery Contact Probes--Double Ended", Interconnect Devices,
Inc., 5101 Richland Ave., Kansas City, KS 66106, 1 page of product
information, undated..
|
Primary Examiner: Donovan; Lincoln
Assistant Examiner: Zarroli; Michael C.
Attorney, Agent or Firm: Daly, Crowley, & Mofford,
LLP
Claims
What is claimed is:
1. An RF system comprising:
an RF element having at least one conductive pad and a ground pad;
and
an RF connector comprising:
a conductive support having at least one aperture;
an electrical insulator disposed within said aperture of said
conductive support and having an aperture,
a conductive contact having a portion disposed within said aperture
of said electrical insulator and a compliant end adjacent to an end
of said aperture and capable of being compressed when said
compliant end contacts said conductive pad of said RF element;
and
a compliant conductive member disposed concentrically around said
conductive contact and electrically insulated from said conductive
contact by said electrical insulator, wherein said compliant
conductive member contacts said ground pad of said RF element when
said compliant end of said conductive contact contacts said
conductive pad of said RF element.
2. The RF system of claim 1 wherein said conductive contact
comprises a selected one of a Fuzz Button.RTM., a watch band pin,
and a bellows.
3. The RF system of claim 1 wherein said conductive contact has a
second end adjacent to a second end of said aperture of said
electrical insulator.
4. The RF system of claim 3 wherein said second end of said
conductive contact is compliant.
5. The RF system of claim 1 wherein said RF connector further
comprises a securing mechanism for securing said conductive support
to said RF element.
6. The RF system of claim 5 wherein said RF element has a plurality
of conductive pads and said RF system comprises a plurality of said
RF connectors, each comprising a conductive contact capable of
being compressed when said compliant end contacts a respective one
of said plurality of conductive pads of said RF element.
7. An RF system comprising:
an RF element having at least one conductive pad and a ground pad
disposed adjacent to said conductive pad; and
an RF connector comprising:
a conductive support having at least one aperture;
an electrical insulator disposed within said aperture of said
conductive support and having an aperture;
a conductive contact having a portion disposed within said aperture
of said electrical insulator and a compliant end adjacent to an end
of said aperture and capable of being compressed when said
compliant end contacts said conductive pad of said RF element and
said conductive support contacts said RF element; and
a conductive member electrically insulated form said conductive
contact by said electrical insulator, wherein said conductive
member contacts said ground pad when said compliant end contacts
said conductive pad, wherein said ground pad of said RF element is
disposed concentrically around said conductive pad and said
conductive member comprises a compressible annular ring.
8. An RF connector comprising:
a substantially rigid conductive support having at least one
aperture;
an electrical insulator disposed within said aperture of said
conductive support and having an aperture;
a conductive contact having a portion disposed within said aperture
of said electrical insulator and a compliant end adjacent to an end
of said aperture and capable of being compressed when said
compliant end contacts a conductive pad of an RF element; and
a compliant conductive member disposed in contact with said
substantially rigid conductive support and electrically insulated
from said conductive contact by said electrical insulator, wherein
said compliant conductive member and said substantially rigid
conductive support contact a ground pad of said RF element when
said compliant end of said conductive contact contacts said
conductive pad of said RF element.
9. The RF connector of claim 8 wherein said conductive contact
comprises a selected one of a Fuzz Button.RTM., a watch band pin,
and a bellows.
10. The RF connector of claim 8 wherein said conductive contact has
a second end adjacent to a second end of said aperture of said
electrical insulator.
11. The RF connector of claim 10 wherein said second end of said
conductive contact is compliant.
12. An RF connector comprising:
a conductive support having at least one aperture;
an electrical insulator disposed within said aperture of said
conductive support and having an aperture;
a conductive contact having a portion disposed within said aperture
of said electrical insulator and a compliant end adjacent to an end
of said aperture and capable of being compressed when said
compliant end contacts a conductive pad of an RF element and said
conductive support contacts said RF element;
a conductive member electrically insulated from said conductive
contact by said electrical insulator, wherein said conductive
member contacts a ground pad of said RF element when said compliant
end contacts said conductive pad, wherein said ground pad of said
RF element is disposed concentrically around said conductive pad
and said conductive member comprises a compressible annular
ring.
13. A method of making an RF connection comprising the steps
of:
providing a conductive support having at least one aperture;
providing an electrical insulator having an aperture;
inserting said electrical insulator into said aperture of said
conductive support;
providing a conductive contact having at least one compliant
end;
providing a compliant conductive member disposed concentrically
around said conductive contact and electrical insulated from said
conductive contact by said electrical insulator;
inserting said conductive contact into said aperture of said
electrical insulator with said at least one compliant end adjacent
to an end of said aperture; and
securing said conductive support to an RF element having a
conductive pad and a ground pad, with said compliant end of said
conductive contact being compressed against said conductive pad and
said compliant conductive member being compressed against said
ground pad.
14. The method of claim 13 wherein the step of providing a
conductive contact comprises the step of providing the conductive
contact to include a selected one of a Fuzz Button.RTM., a watch
band pin, and a bellows.
15. The RF system of claim 1 wherein said ground pad of said RF
element is disposed concentrically around said conductive pad.
16. The method of claim 13 wherein said securing step comprises the
step of securing said conductive support to an RF element having a
ground pad disposed concentrically around said conductive pad.
17. An RF system comprising:
an RF element having at least one conductive pad; and
an RF connector comprising:
a conductive support having at least one aperture;
an electrical insulator disposed within said aperture of said
conductive support and having an aperture; and
a conductive contact comprising a compliant portion disposed within
said aperture of said electrical insulator and a substantially
rigid portion adjacent to an end of said aperture, wherein said
substantially rigid portion compresses said compliant portion when
said substantially rigid portion contacts said conductive pad of
said RF element wherein said compliant portion of said conductive
contact comprises a Fuzz Button.RTM..
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH
Not applicable.
BACKGROUND OF THE INVENTION
Radio Frequency (RF) modules often include male pin contacts for
permitting electrical interconnections to be made to RF and
DC/logic circuitry supported by the module. Various types of
connectors are suitable for mating with such pins, including
coaxial connectors. Coaxial connectors generally include a
conductive outer housing containing a dielectric, with a
cylindrical aperture through the dielectric capturing a mating
female contact. The male pin contact, attached to the RF module, is
inserted into the female contact which, together provide the center
conductor of the connector. The ratio of the outer diameter of the
center conductor to the inner diameter of the housing determines
the impedance of the RF connection. Various mechanisms, such as
screw threads, are suitable for mechanically coupling the RF
connector housing to the RF module.
In many applications, such as phased-array antennas, RF modules
include numerous male pin contacts, sometimes well in excess of
one-thousand. Often in such applications, many RF connectors are
supported by a single support structure, such as a plate or other
type of holder, which is secured to the RF module.
The pins attached to an RF module are generally required to have
very precise position tolerances, particularly in applications in
which many RF connectors are supported by a single support
structure. This is because tolerance variations are compounded when
many RF connectors are supported in fixed positions relative to one
another. Another critical parameter of the pins is that they extend
from the RF module at a precise ninety-degree angle in order to
ensure proper alignment with the respective RF connector during
assembly. Assembly of an RF module to one or more RF connectors is
time consuming due to the frailty of the pins and the conventional
arrangement of including several RF pins, often closely spaced, on
the module. Any tolerance variations can result in broken or bent
pins, which may require that the entire RF module be replaced,
thereby causing the yield of RF modules, which are often complex
and expensive themselves, to suffer. Pins are often attached to an
RF module by a brazing or soldering process, which tends to be
rather expensive, particularly when strict tolerance requirements
exist.
BRIEF SUMMARY OF THE INVENTION
The invention is directed to an RF connector comprising an
electrical insulator having an aperture and a conductive contact
having at least a portion disposed within the aperture of the
insulator. The conductive contact has at least one compliant end
adjacent to an end of the aperture for contacting a conductive pad
of an RF element, such as an RF module or RF connector, in use. The
conductive contact end is compliant in the sense that it is
compressible. In use, the compliant end of the conductive contact
is compressed against the conductive pad of the RF element to
effect electrical connection. The compliant end of the conductive
contact may or may not extend through the adjacent end of the
insulator aperture.
A conductive support is provided for supporting one or more RF
connectors of the type described above and for providing a ground
connection to the RF element. One such support is provided in the
form of a conductive plate and includes a plurality of apertures,
each of which has an RF connector, comprising an electrical
insulator and a conductive contact, disposed therein.
In use, the support is secured to the RF element, thereby causing
the compliant end of each supported conductive contact to be
compressed against a respective conductive pad of the RF element
and causing the support to contact a ground portion of the RF
element. The ratio of the outer diameter of the conductive contact
to the inner diameter of the support aperture can be varied in
order to vary the impedance of the RF interconnection.
With this arrangement, an RF connector is provided which overcomes
several drawbacks associated with conventional RF interconnection
schemes. Significantly, the RF connector of the present invention
does not require the use of male or female pins attached to the RF
element to provide electrical interconnection. Rather, the RF
connector contacts a conductive pad on the RF element. The
elimination of pins on the RF element significantly decreases the
cost and time associated with manufacturing and assembling the RF
system, such as a phased array antenna which requires a significant
number of RF interconnections to be made. Further, with the
arrangement described herein, the volumetric space required for the
RF connection can be less than is required with the use of standard
coaxial connectors.
The RF element may take the form of an RF module which supports RF
circuitry or a standard RF connector. Further, the RF connector of
the present invention may or may not include RF circuitry for
electrical connection to one or more RF elements. The conductive
contact has a second end adapted for contacting the second RF
element, which second end may or may not be compliant.
The conductive contact may take various forms suitable for
providing at least one compliant end. As one example, the
conductive contact includes a "watch band" or "POGO" pin,
comprising at least one spring-loaded pin capable of being
compressed. In a further embodiment, the conductive contact
includes a bellows device comprising a plurality of deformable
folds which are compressible. A further suitable conductive contact
includes a Fuzz Button.RTM. which comprises a conductor formed into
a plug-shaped compressible mesh. Alternatively, the conductive
contact may include Belleville washers or an element comprised of
an elastomer loaded with conductive particles. Preferably, the
conductive contact is plated with gold in order to ensure low,
stable RF losses in benign or adverse environments.
The conductive contact may comprise a single element of one of the
above-described, or other types suitable for providing at least one
compliant end or, alternatively, may comprise more than one
element, in which case at least one of the elements has at least
one compliant end which provides the composite contact with at
least one compliant end. As one example of a composite contact, a
conductive contact includes a Fuzz Button.RTM. element sandwiched
between two rigid conductive plugs. In this case, the exposed ends
of the conductive plugs are rendered compliant because they are
capable of being compressed due to compression of the sandwiched
Fuzz Button.RTM. element.
The RF connector of the present invention may include an "outer"
conductive member electrically insulated from the "center"
conductive contact by the electrical insulator. In use, the outer
conductive member simultaneously contacts a ground pad of the RF
element when the compliant end of the center conductive contact is
compressed against the conductive pad of the RF element. In one
embodiment, the ground pad of the RF element is substantially
annular and is disposed concentrically around the center conductive
pad of the RF element and the conductive member of the RF connector
is provided in the form of a compressible annular ring, or o-ring,
in order to provide an RF coaxial interconnection.
Also described is a method of making an RF connection which
includes the steps of providing an electrical insulator with an
aperture, providing a conductive contact having at least one
compliant end, and inserting the conductive contact into the
aperture of the electrical insulator with the compliant end
adjacent to an end of the aperture. Also provided is a support
having an aperture in which the electrical insulator is disposed
and a conductive compressible outer ground pad. In use, the support
is secured to an RF element having a conductive pad, with the
compliant end of the conductive contact compressed against the
conductive pad and the compressible outer ground pad compressed
against a ground portion of the RF element.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing features of this invention, as well as the invention
itself, may be more fully understood from the following description
of the drawings in which:
FIG. 1 shows an RF system including an RF connector according to
the invention;
FIG. 1A is a cross-sectional view of the RF connector of FIG.
1;
FIG. 2 shows an alternate RF connector according to the
invention;
FIG. 3 shows an RF system including an alternate RF connector
according to the invention;
FIG. 4 shows an RF system including a further alternate RF
connector according to the invention;
FIG. 5 is a plan view of a support plate suitable for supporting a
plurality of RF connector,;
FIG. 6 shows an RF system including an RF connector utilizing a
watch band pin as the conductive contact;
FIG. 6A is an enlargement of the watch band pin conductive contact
of the RF connector of FIG. 6;
FIG. 7 shows an RF system including an RF connector utilizing a
bellows as part of the conductive contact;
FIG. 7A is an enlargement of the bellows conductive contact of the
RF connector of FIG. 7; and
FIG. 8 shows a further alternate RF connector utilizing Belleville
washers as part of the conductive contact.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, an RF system 10 includes an RF element 14 and
an RF connector 18. The RF element 14 may take various forms and be
provided for various RF applications, including RF modules, such as
T/R modules for radar systems, and standard RF connectors. In
general, the RF element 14 carries one or more RF signals to be
electrically connected to RF circuitry which may or may not be
contained within the element 14. An RF element in the form of an RF
module generally contains RF circuitry, whereas an RF element in
the form of a standard RF connector generally carries electrical
signals to a further module. The RF element 14 may additionally
carry one or more DC/logic signals to circuitry which may or may
not be contained within the element. Some RF modules 14 include
microstrip, stripline, and/or coaxial RF transmission lines, often
provided on a multilayered ceramic structure (see, for example,
FIGS. 3, 4 and 6).
The RF connector 18 in FIG. 1 provides electrical connection to the
RF element 14 without requiring that the element have pins attached
thereto. Rather, the RF element 14 generally includes at least one
conductive pad 22 and a ground portion for purposes of permitting a
coaxial electrical connection to be made to the element. Often, the
RF element 14 includes a plurality of pads 22 carrying RF and/or
DC/logic signals for electrical connection to RF circuitry. The RF
connector 18 will be described in conjunction with making a single
RF connection to a single conductive pad 22 on the element 14 for
simplicity of illustration. However, it will be appreciated by
those of ordinary skill in the art that the RF connector 18 may be
modified to provide RF and/or DC/logic connections to a plurality
of conductive pads on the element.
The RF connector 18 includes a dielectric, or electrical insulator
26 having a bore, or aperture 28 therethrough and a conductive
contact 32 disposed through at least a portion of the aperture 28.
The conductive contact 32 has at least one compliant end 36 which
is capable of being compressed in use, as described further below.
The compliant end 36 of the conductive contact 32 may extend
through the adjacent end of the aperture 28 as shown, or
alternatively, may terminate within the aperture.
A conductive support 40 is provided for supporting the electrical
insulator 26 and conductive contact 32 and for providing a ground
connection to the RF element 14. More particularly, the support 40
has an aperture 52 adapted to receive the electrical insulator 26,
as shown.
Referring also to FIG. 1A, a cross-sectional view of a portion of
the RF connector 18 taken along line 1A--1A of FIG. 1 reveals that
both the insulator 26 and contact 32 have substantially circular
(i.e., coaxial) cross-sectional shapes. However, as will be
appreciated to those of ordinary skill in the art, other
cross-sectional shapes for both the electrical insulator 26 and the
conductive contact 32 are possible without departing from the
spirit and scope of the invention. The impedance of the RF
connection provided by the connector 18 is a function of the ratio
of the outer diameter of the conductive contact 32 to the inner
diameter of the aperture 52 in the support 40.
The connector 18 may electrically connect the RF element 14 to
circuitry provided as part of the connector 18 (not shown) and/or
may electrically connect the RF element 14 to a second RF element
44, as shown. Like the first RF element 14, the second RF element
44 carries one or more RF and/or DC/logic signals to be
electrically connected to circuitry which may or may not be
contained within the element 44 and typically takes the form of an
RF module or a standard RF connector. A second end 48 of the
conductive contact 32 which contacts the second RF element 44 in
use may or may not be compliant and may or may not extend through
the adjacent end of the insulator aperture 28. In the embodiment of
FIG. 1, the second end 48 of the contact 32 is compliant and
extends through the adjacent end of the aperture 28.
The conductive contact 32 may take various forms in order to
provide the characteristic of having at least one compliant,
compressible end. One suitable conductive contact, shown in FIG. 1,
is a Fuzz Button.RTM. which is a generally cylindrical element
comprising one or more conductors formed into a plug-shaped mesh.
The Fuzz Button.RTM. is comprised of materials such as
phosphor-bronze, molybdenum and beryllium copper plated with nickel
or gold. Fuzz Button.RTM. is a registered trademark of Tecknit.RTM.
of Cranford, N.J. Other suitable conductive contact elements and
combinations of elements are described below.
The electrical insulator 26 may be comprised of any dielectric
material having suitable dielectric and mechanical characteristics,
such as plastics, ceramics or Teflon.RTM., and may be fabricated by
various techniques, including molding. Generally, the material of
the insulator 26 is selected to provide a predetermined dielectric
constant as a function of the frequency of the RF signals carried
by the connector.
The conductive support 40 which provides the ground connection for
the resulting coaxial connection may take various forms, such as
the plate shown in FIG. 1, and may be comprised of various
conductive materials. As one example, the support 40 is comprised
of aluminum and the aperture 52 is formed by drilling.
Various techniques are suitable for assembling the RF connector 18
of FIG. 1. For example, the electrical insulator 26 may be press
fit into the aperture 52 of the support 40. Alternatively, an
adhesive may be used to secure the insulator 26 within the aperture
52. However, easily reversible assembly techniques, such as press
fitting, may be preferable due to ease of disassembly for testing,
manufacturing and repair purposes.
In the illustrative embodiment, the conductive contact 32 is
"light" press fit into the aperture 28 of the electrical insulator
26. In some applications, it may be desirable to taper the aperture
28 of the insulator 26 in order to facilitate this press fit
relationship. The technique chosen for securing the conductive
contact 32 within the aperture 28 of the insulator must permit at
least one end portion (i.e., the compliant end) of the contact to
be free-moving relative to the insulator 26 in order to permit
compression in use. Here again, easily reversible assembly
techniques, such as press fitting, may be preferable due to ease of
disassembly for testing, manufacturing and repair purposes.
In use, the RF connector 18 is aligned with, and secured to the RF
element 14 such that the first compliant end 36 of the conductive
contact 32 is compressed against the conductive pad 22 of the
element 14 and at least a portion of the conductive support 40
contacts a ground portion of the RF element. The RF connector 18
may be secured to the RF element 14 by various mechanisms (not
shown), such as screws, clamps and/or epoxy.
In applications in which the RF connector 18 interconnects the
first RF element 14 with a second RF element 44 as shown in FIG. 1,
the second RF element 44 and the RF connector 18 are likewise
secured together, thereby causing the second compliant end 48 of
the conductive contact 32 to be compressed against a conductive pad
46 of the second RF element 44 and a portion of the conductive
support 40 to contact a ground portion of the RF element 44.
Referring to FIG. 2, an alternate RF connector 60 includes an
electrical insulator 64 having an aperture 68 therein in which a
conductive contact 72 is disposed. The conductive contact 72 may be
comprised of more than one conductive element. In the embodiment of
FIG. 2, the conductive contact 72 includes a Fuzz Button.RTM.
element 74, a first, rigid conductive plug 76 terminating at a
first compliant end 78 of the contact and a second, rigid
conductive plug 80 terminating at a second compliant end 82 of the
contact.
In use, the RF connector 60 is disposed between RF elements 14, 44
(FIG. 1) to provide electrical interconnection therebetween in the
same manner as described above in conjunction with FIG. 1. More
particularly, when the RF connector 60 is secured between elements
14 and 44, the end 78 of plug 76 is urged inward toward the Fuzz
Button.RTM., thereby compressing the Fuzz Button.RTM. and the end
82 of the plug 80 is urged inward toward the Fuzz Button.RTM.,
thereby further compressing the Fuzz Button.RTM.. In this way, the
compressibility of the Fuzz Button.RTM. 74 is effectively
transferred to the plugs 76, 80 rendering the first and second ends
78, 80 of the composite conductive contact 72 compliant.
The RF connector 60 further includes a conductive support 86. In
the embodiment of FIG. 2, the support 86 is provided in the form of
a relatively thin conductive sheath covering the dielectric 64. As
will be appreciated by those of ordinary skill in the art, the
support may take various forms having various dimensions. In use,
at least a portion of the conductive support 86 contacts a ground
portion of the RF elements to thereby effect a coaxial RF
connection.
Referring to FIG. 3, an RF system 100 includes an RF connector 104
suitable for providing electrical interconnection to an RF element
108. The RF connector 104 and RF element 108 are disposed over a
floor 112 of a structural housing member or heat sink (not shown)
in which the RF system 100 is disposed. In the embodiment of FIG.
3, the RF element 108 is provided in the form of an RF module.
The RF element 108 includes a horizontally oriented multilayered
ceramic structure supporting a strip transmission line 116 having
an electrically isolated conductive pad 120 disposed on an edge of
the element 108 adjacent to the RF connector 104. The ground plane
of the strip transmission line 116 is provided by the RF element
housing floor 112 and is electrically connected to a ground pad 122
disposed concentrically around the conductive pad 120 for
contacting a ground plane of the RF connector 104. It should be
noted that RF element 108, may have a variety of internal
configurations and of particular relevance are the external
features of conductive pad 120 and ground pad 122.
In the embodiment of FIG. 3, the RF connector 104 is provided as
part of a coaxial cable mounting block. To this end, the connector
104 includes a coaxial cable 124 having a center conductor 140
electrically insulated from a ground shield 146 by an electrical
insulator 150, as shown. The RF connector 104 provides electrical
interconnection between the RF element 108 and the coaxial cable
124 extending from the RF connector.
The RF connector 104 includes an electrical insulator 128 having an
aperture 130 in which a conductive contact 134 is disposed. The
electrical insulator 128 is, in turn, disposed in an aperture 138
of the connector 104.
The conductive contact 134 includes a Fuzz Button.RTM. element 152
and a conductive cap 158. The Fuzz Button.RTM. 154 extends through
an end of the aperture 130 to terminate it a compliant end 160. The
opposite end of the Fuzz Button.RTM. 154 is disposed in contact
with the conductive cap 158. The conductive cap 158 includes a
detent having a size and shape complementary to the center
conductor 140 of the coaxial cable 124. In assembly, the tip of the
coaxial cable center conductor 140 is disposed in the detent of the
cap 158, as shown.
In use, the RF connector 104 and the RF element 108 are secured
together by any of various conventional mechanisms. With the
connector and element secured together, the exposed end 160 of the
Fuzz Button.RTM. 154 is compressed against the pad 120 of the RF
element. Further, the opposite end of the Fuzz Button.RTM. element
is compressed against the conductive cap 158, thereby electrically
connecting the coaxial cable 124 to the strip transmission line 116
via the Fuzz Button.RTM. 154 and the conductive cap 158. The ground
path in the embodiment of FIG. 3 is provided by the RF element
housing floor 112 in contact with ground pad 122 which, in
assembly, contacts a ground pad of the RF connector 104.
Referring to FIG. 4, a further alternate RF system 170 includes an
RF connector 174 and an RF element 178. The RF element 178 is
provided in the form of an RF module and includes a horizontally
oriented ceramic structure 192. The element 178 supports a strip
transmission line including a ground plane and a conductor 198
connected by a via 216 to a monolithic microwave integrated circuit
(MMIC) 190 housed within the element 178. The ground plane is
provided by a housing cover 184, housing walls 188, and a housing
floor 189 of the element 178. The conductor 198 and ground plane
are accessible via conductive pads 182 and 186, respectively,
disposed on an end 180 of the element, with the ground pad 186
having a substantially annular shape and being disposed
concentrically around the conductor pad 182 in the form of a
coaxial transmission line. It will be appreciated by those of
ordinary skill in the art that the pads 182 and 186 can be
eliminated if the adjacent portions of the RF element housing are
plated with gold or silver.
The RF connector 174 includes an electrical insulator 194 having an
aperture 196 in which a conductive contact 200, comprising a
contact 202 and a Fuzz Button.RTM. 204, is disposed. The RF
connector 174 further includes a support 208 providing an outer
conductor and having an aperture 210 in which the electrical
insulator 194 is disposed, as shown.
A compliant conductive member 214 is disposed concentrically around
the Fuzz Button.RTM. 204. The compliant conductive member 214 is
electrically isolated from the Fuzz Button.RTM. 204 by the
electrical insulator 194, as shown.
In the illustrative embodiment, the compliant conductive member 214
is provided in the form of a conductive annular ring. The
conductive member 214 may be comprised of various compressible,
conductive materials, including silicone loaded with conductive
particles such as aluminum, silver, or gold, and gold-plated wire
mesh like the materials used in the Fuzz Button.RTM. 204.
Various techniques are suitable for securing the annular conductive
member 214 to the RF connector 174. In the illustrative embodiment,
the support 208 has a groove 212 in which the annular conductive
member 214 is seated. The annular member 214 may be held in place
in the groove 212 by any suitable technique, such as a friction, or
press fit arrangement or with the use of an adhesive.
In use, the RF connector 174 and the RF element 178 are secured
together, with the annular conductive member 214 and the Fuzz
Button.RTM. 204 concentrically aligned with the conductor pad 182.
With this arrangement, the Fuzz Button.RTM. 204 is compressed
against the conductor pad 182 and the annular conductive member 208
is compressed against the housing ground plane via ground pad 186,
thereby effecting a coaxial RF connection.
The contact 200 has a first end in contact with the Fuzz
Button.RTM. 204 and a second end 206 provided in the form of a
female socket or a male pin capable of accepting a standard RF
connector of the opposite type.
Referring to FIG. 5, an illustrative conductive support plate 220
for use with an RF connector of the type described herein is shown
to include a plurality of apertures 224a-224z. The support plate
may be comprised of any material having a conductively plated
(anti-corrosive) surface exhibiting suitable strength
characteristics, such as steel. Further, the plate 220 may include
any number of apertures 224a-224z arranged in various patterns
suitable for accommodating RF interconnection to conductive pads on
one or more RF elements.
Each of the apertures 224a-224z is adapted for receiving an
electrical insulator and conductive contact arrangement, such as of
the type described above in conjunction with FIGS. 1-4. As noted
above, the electrical insulators may be held in place in the
apertures 224a-224z by various mechanisms, including a press fit
arrangement.
In use, one or more RF elements are secured to the plate 220, as
described above. Various mechanisms are suitable for providing this
mechanical interconnection, such as the use of screws 126a-126n
disposed through screw holes 228a-228n as shown, or with epoxy
and/or clamps. The particular number, size and location of the
screw holes 228a-228n or other mounting mechanism is a function of
the particular application.
Referring to FIG. 6, a further alternate RF system 240 includes an
RF connector 242 interconnecting a first RF element 246 provided in
the form of an RF module and a second RF element 248 provided in
the form of a standard coaxial connector. The RF connector 242,
like those described above, includes an electrical insulator 250
having an aperture 252 in which a conductive contact 256 is
disposed. The conductive contact 256 of FIG. 6 is provided in the
form of a "watch band" pin, which is sometimes referred to as a
"POGO" pin, as will be described. Suffice it to say that the
conductive contact 256 has first and second compliant, compressible
ends 258, 260.
The RF connector 242 further includes an outer conductor element,
or support plate 264 having an aperture provided in the form of a
machined hole 266 through which the electrical insulator 250 is
disposed. Also provided are two substantially annular, compressible
conductive members 270, like the annular ring 214 of FIG. 4,
disposed in grooves 268 of the plate 264 and electrically isolated
from the conductive contact 256 by the insulator 250, as shown.
The RF element 246 includes a multilayered ceramic structure 286
supporting a transmission line 292 and ground planes 298 arranged
to provide a 50 ohm strip transmission line. Although RF element
246, RF connector 242, and RF element 248 are shown to be
vertically oriented, it will be appreciated by those of ordinary
skill in the art that the entire assembly can be rotated by ninety
degrees in use in order to render the multilayered structure 286
horizontally oriented. A conductive pad 282 is electrically
connected through a via 272 to the strip transmission line 292 and
a ground pad 284 is electrically connected through vias 296 to the
ground planes 298. The ground pad 284 is substantially annular and
is disposed concentrically around the conductor pad 282 in the form
of a coaxial transmission line. The coaxial RF connector element
248 has a center conductor 290 and threads 294 for connection to
other RF elements, connectors and/or circuitry (not shown).
Referring to the watch band pin enlargement of FIG. 6A, the pin 256
includes a housing 262 sized and shaped for being inserted into the
aperture 252 of the electrical insulator 250. At least one, and in
the illustrative embodiment both ends 258, 260, of the contact 256
are spring-loaded and thus, are capable of being compressed.
Suitable watch band pins are available from Interconnect Devices,
Inc. of Kansas City, Kans. under part numbers 100404-00 and
100422-00. In use, when the RF element 246 and coaxial RF connector
248 are secured to the RF connector 242, the first end 258 of the
contact 256 is compressed against the center conductor 282 of the
RF element 246 and the second end 260 of the contact 256 is
compressed against the center conductor 290 of the coaxial RF
connector element 248. Further, the compressible annular ring 268
is compressed against the ground pad 284 of the RF element 246.
Referring to FIG. 7, another alternate RF system 300 includes an RF
connector 304 having an electrical insulator 308 with an aperture
310 in which a conductive contact 312 is disposed. The conductive
contact 312 includes an integral compressible bellows 316, as will
be described. The RF connector 304 further includes a support plate
320 having an aperture 324 in which the electrical insulator 308 is
disposed.
The RF connector 304 is adapted for interconnecting first and
second RF elements 328, 330 which, in the embodiment of FIG. 7, are
provided in the form of standard RF connectors. Each of the RF
elements 328, 330 shown in FIG. 7 thus includes a center conductor
342, 344 and a threaded portion 348, 350 for connection to other RF
elements, connectors and/or circuitry (not shown),
respectively.
The conductive contact 312 has a first end 334 adapted for
contacting the center conductor 342 of the first RF element 328 in
use and a second, compliant end 338. More particularly, the
conductive contact 312 includes a bellows 316 and a conductive pin
318, with the conductive pin 318 disposed within the aperture 310
of the insulator 308. One end 334 of the conductive pin 318
terminates slightly beyond an end of the insulator 308 in a gap 352
between the end of the insulator and the edge of the plate 320
adjacent to the RF element 326. The bellows 316 is at the opposite
end of the pin 318 and extends through a portion 354 of the
aperture 324, to terminate beyond the edge of the plate 320
adjacent to the RF element 330, as shown.
Referring to the enlargement of the bellows in FIG. 7A, the bellows
316 is comprised of a flexible accordion section 360 integrally
formed with and extending from a hollow cap section 362. The
accordion section 360 comprises a plurality of flexible folds which
are compressible against one another. The bellows may be comprised
of various flexible, conductive materials, such as silver or gold
plated nickel, by any suitable technique such as electroforming.
Suitable bellows devices are available from Servometer Corporation
of Cedar Grove, N.J. under the part number 2510.
In assembly, the end of the pin 318 adjacent to the bellows is
inserted into the hollow cap 362 of the bellows and secured in
place by any suitable joining process, such as soldering or spot
welding. It will be appreciated by those of ordinary skill in the
art however, that other schemes are suitable for coupling the
bellows to the pin 318. The resulting conductive contact 312,
including the bellows 316 and the conductive pin 318, is inserted
into the insulator aperture 310 with a "slide-fit" arrangement.
In use, the RF connector 304 is brought into alignment with the RF
elements 328, 330 such that the center conductor 344 of the RF
element 330 is aligned with the end 338 of the bellows 316 and the
center conductor 342 of the RF element 328 is aligned with the end
334 of the conductive pin 318. The RF elements 328, 330 and the RF
connector 304 are secured together by any suitable mechanism,
thereby causing the bellows 316 to compress against the conductor
344, causing the conductor 342 to contact to the end 334 of the
conductive pin 318 and causing the conductive support 320 to
contact ground portions of the RF elements 328 and 330.
Referring to FIG. 8, an alternate RF connector 380 includes an
electrical insulator 382 having an aperture 384 in which a
conductive contact 386 is disposed. The conductive contact 386 has
first and second compressible, sliding ends 412, 414, respectively.
The connector 380 further includes a conductive support plate 388
having an aperture 390 in which the electrical insulator 382 is
disposed, as shown.
The conductive contact 386 includes a first member 394 having a
post 400 extending therefrom and a second portion 404 having a
detent 408 therein. The post 400 and detent 408 are sized and
shaped to permit an end of the post 400 to slide fit within the
detent 408, as shown. A plurality of compressible elements 410 are
disposed on the post 400. In the illustrative embodiment, the
compressible elements 410 are provided in the form of Belleville
washers or bellows. The number, size and material of the elements
410 are selected to provide a predetermined spring constant to suit
a particular application. The conductive contact 386 is disposed in
the insulator aperture 384 with a "slide-fit" arrangement.
In use, the RF connector 380 is adapted for being positioned
between two RF elements in order to provide electrical connection
therebetween in the manner described generally above in connection
with FIG. 1. That is, the RF connector 380 is secured to the RF
elements such that the exposed end 412 of the connector portion 394
is compressed against a conductive pad of one of the elements and
the exposed end 414 of the connector portion 404 is compressed
against a conductive pad of the other one of the elements, thereby
compressing the Belleville washers 410. Further, the conductive
support 388 contacts ground portions of the RF elements in order to
effect an RF coaxial connection.
It will now be apparent to those of ordinary skill in the art that
the RF connectors described herein overcome several drawbacks
associated with conventional RF interconnection schemes.
Significantly, the RF connectors described herein provide
electrical connection to one or more conductive pads, rather than
to pins. The elimination of pins on RF elements reduces the
manufacturing, assembly and repair costs of the RF elements and,
further, increases the yield of such elements.
Further, the cross-sectional length "L" (FIGS. 1-2 and 6-8) and,
thus, the volume of the RF connectors described herein can be
smaller than heretofore possible since there are no minimum length
requirements imposed by pins extending from the RF element.
Further, a single screw or other securing mechanism, through the
support (e.g., support 40 of FIG. 1) can provide sufficient
coupling force to mate many connectors, such as on the order of
ten. Thus, the space required around each conductive contact is
less than would be required for individual screw thread coupling
mechanisms. In particular, the cross-sectional length "L" and
volume of the RF connector is dictated only by the availability of
conductive contact elements of small dimensions and manufacturing
considerations regarding handling and assembly of the connector.
For example, Fuzz Button.RTM. embodiment of FIG. 1, the
cross-sectional length "L" of the connector 18 may be on the order
of 0.050 inches.
These advantages are achieved with the use of a compliant,
compressible member as, at least part of, the conductive contact of
the RF connector. As described herein, various element types and
combinations thereof are possible for providing the conductive
contact and are within the spirit and scope of the present
invention. Significant to the suitability of the connector
arrangements described herein to making RF interconnections is the
plating, of the conductive contact in order to minimize insertion
and return losses and the ability to tailor the impedance of the RF
interconnection by varying the ratio of the conductive contact
outer diameter to the inner diameter of the aperture in the
conductive support in which the insulator is disposed. Further, as
will be apparent to those of ordinary skill in the art, the
connectors described herein may be used to provide connection to
DC/logic signals in addition to RF signals.
Having described the preferred embodiments of the invention, it
will now become apparent to one of ordinary skill in the art that
other embodiments incorporating their concepts may be used. It is
felt therefore that these embodiments should not be limited to
disclosed embodiments but rather should be limited only by the
spirit and scope of the appended claims. All publications and
references cited herein are expressly incorporated herein by
reference in their entirety.
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